无奇异双向犁翻转机构运动学分析与性能优化

翻转机构是翻转式双向犁的核心工作部件,翻转过程中如何避免或越过奇异位置是此类机构设计和应用时必须要解决的问题。根据机构学理论,将冗余自由度引入双向犁翻转机构的设计中,得到一种新型2自由度运动冗余翻转机构。首先,通过建立机构的位置和速度约束方程,得到机构的输入、输出雅可比矩阵,以输入、输出雅可比矩阵的行列式不等于零为判定条件,推导出犁架实现无奇异往复翻转运动时,机构应满足的几何约束条件。其次,基于力传递矩阵和速度雅可比矩阵,对机构的力传递性能、刚度性能和承载力性能进行分析,总结机构设计参数对各项性能指标的影响规律,得到了机构综合性能优选时的参数设置范围。所得结论可为新型特别是重型双向犁的研发提供设计思路和参考依据。

Kinematic Analysis and Performance Optimization of Singularity-Free Turnover Mechanism in Two-way Plow

Turnover mechanism is the core component of reversible two-way plow.How to avoid or exceed the singular position is a problem which must be solved in the process of designing and applying this mechanism.Firstly,based on mechanism and machine theory,a novel type of singularity-free kinematically redundant turnover mechanism with two degrees of freedom was proposed and introduced into design of two-way plow.Secondly,the position and velocity equations of this mechanism were established according to geometric constraints,and the Jacobian matrices including input and output were derived.Taking the determinant of the input and output Jacobian matrices as identification,singularities of all introduced variants were analyzed when the plow realizes turnover motion with singularity-free capability.Based on the transfer matrix of force and Jacobian matrix of velocity,the force transmissibility performance、stiffness performance and payload performance of the mechanism were analyzed,and effects of link lengths to these performances were summarized.Conclusions obtained in this paper can provide a theoretical basis for the design of heavy-duty turnover plow.